changed instances of .count() > 0 to if ___ in ___
implemented minimum comment length for chain add

implemented a minimum length for a comment to have for it to be
considered worth adding to the chain. the thought here is that very
short comments contain no valuable content and clutter up/skew the
chain, leading to worse responses generated.
rearranged drone fleet to sort by selectivity

this way the "pickiest" drones have first picks at the comments as they
come by, because as soon as one drone takes a comment, it isn't offered
to any others. Also decreased the weight of watdrone by 10 points.